TestJpaRepository Documentation

Overview

TestJpaRepository is an abstract class that implements the JpaRepository interface (from spring-data-jpa), designed to simulate a JpaRepository in a testing environment. This class provides functionality similar to a JpaRepository, allowing you to verify data access logic without a test database. It operates entirely in-memory, making it fast and independent of any external database.

Getting Started

1. Create a repository class for testing that inherits from TestJpaRepository.
2. Pass the ID field name to the constructor.
3. In test class, define a repository field with the repository interface type and initialize it with what you made at 1.

// Create a repository as singleton for testing easily
// Pass the ID field name "id" to the constructor
// Example says Beverage Entity use PK field name as "id"
object TestBeverageRepository : TestJpaRepository<Beverage, Long>("id"), BeverageRepository {
}

// Initialize data in test repositories by TestRepositorySupport 
abstract class TestRepositorySupport {
    @AfterEach
    fun tearDown() {
        TestBeverageRepository.initalize() // defined at TestJpaRepository
    }
}

class TestExample : TestRepositorySupport() {
    private val beverageRepository = TestBeverageRepository
}

Code

You can refer to the TestJpaRepository, TestRepositorySupport and example use case below.

• TestJpaRepository
• TestRepositorySupport
• RepositoryTest (example)

Advantages

• No Database Dependency: Enables testing without the need for a database.
• No Mocking Library Required: Removes the need to use mocking libraries.
• Fast Execution: Tests run faster as there is no database I/O.
• Consistency with Production: If you use JpaRepository in production, you can leverage the same structure in tests.

Not Suitable For

• Large Data Sets: Not ideal for tests involving large amounts of data (should consider OOM).
• Multi-threaded Environment: Inappropriate for tests requiring multi-threaded access. It works on single-threaded only.

Unsupported Features

The following methods throw UnsupportedOperationException as they are not supported in TestJpaRepository:

• findAll(example: Example<S>)
• findAll(example: Example<S>, sort: Sort)
• findAll(example: Example<S>, pageable: Pageable)
• findAll(sort: Sort)
• findBy(example: Example<S>, queryFunction: Function<FluentQuery.FetchableFluentQuery<S>, R>)
• exists(example: Example<S>)
• findOne(example: Example<S>)
• count(example: Example<S>)

Additionally:

• flush() method does nothing.

License

MIT License